General Information The gypsy moth, Lymantria dispar, is one of North America's most devastating forest pests. The species originally evolved in Europe and Asia and has existed there for thousands of years. In either 1868 or 1869, the gypsy moth was accidentally introduced near Boston, MA by E. Leopold Trouvelot. About 10 years after this introduction, the first outbreaks began in Trouvelot's neighborhood and in 1890 the State and Federal Government began their attempts to eradicate the gypsy moth. These attempts ultimately failed and since that time, the range of gypsy moth has continued to spread. Every year, isolated populations are discovered beyond the contiguous range of the gypsy moth but these populations are eradicated or they disappear without intervention. It is inevitable that gypsy moth will continue to expand its range.
The gypsy moth is known to feed on on the foliage of hundreds of species of plants in North America but its most common hosts are oaks and aspen. Gypsy moth hosts are located through most of the coterminous US but the highest concentrations of host trees are in the southern Appalachian Mtns., the Ozark Mtns., and in the northern Lake States.
Gypsy moth populations are typically eruptive in North America; in any forest stand densities may fluctuate from near 1 egg mass per ha to over 1,000 per ha. When densities reach very high levels, trees may become completely defoliated. Several successive years of defoliation, along with contributions by other biotic and abiotic stress factors, may ultimately result in tree morality. In most northeastern forests, less than 20% of the trees in a forest will die but occasionally tree mortality may be very heavy.
Forest Effects Despite over 100 years of presence in North America, researchers are still at a loss to explain and predict the extent of the changes in forest vegetation likely to take place through gypsy moth disturbance. A major concern is the potential loss of economically critical and ecologically dominant oak species. Most studies of forest compositional changes with gypsy moth defoliation indicate that less susceptible species will dominate the forest, so in effect, forests may have fewer gypsy moth problems in the future.
Natural Enemies
A variety of natural agents are known to kill gypsy moths in nature. These agents include over 20 insect parasitoids and predators that were introduced over the last 100 years from Asia and Europe. Small mammals are perhaps the most important gypsy moth predator, especially at low population densities. Birds are also known to prey on gypsy moths but at least in North America this does not substantially affect populations. A nucleopolyhedrosis virus usually causes the collapse of outbreak populations and recently an entomopathogenic fungus species has caused considerable mortality of populations in North America.
Gypsy Moth Eggs The female gypsy moth lays between 500 to 1,000 eggs in August. They are laid all at once in a mass that is covered with velvety, buff-colored hair from the female moth's body. The larva starts developing during the remaining warm days of summer. As winter approaches, the tiny larva goes into diapause. That means it shuts down and goes through the winter without growing or developing until spring. The eggs hatch in mid-May, just in time to start munching on new green leaves.
eggmass
Gypsy Moth Larva This stage is also known as caterpillar, the worm-like form of an insect. The larva is covered in long, stiff hairs. When it is very young, it's black. As the larva grows, pairs of colored warts appear running down the center of its back. The warts are red on the rear half and blue near the head. Before the larvae settle down to feed, they will spread out through the forest by "ballooning." This means that the larva climbs to the top of the tree, spins a thread and dangles from it. When a breeze catches the larva, away it goes, usually landing within 150 yards of where it started. Although, on occasion, the larvae are blown long distances. This is one way the gypsy moth travels to new areas. In order to grow, the larva must shed its skin. Gypsy moth caterpillars will shed their skin 4-5 times, about once a week. It is the larval stage of the moth that causes all the damage to trees as the caterpillars feed on leaves. By July, the larvae have reached maturity.
When the gypsy moth population explodes, the feeding larvae can strip trees of leaves. This is called defoliation. Defoliation is very stressful for trees and can leave them so weak that they can be killed by other pests which would not normally bother them. The hungry larvae feed on many types of trees, but they do have their favorites. These are the ones defoliated most frequently. Gypsy Moth Adult This is the adult stage of the insect. The male gypsy moth is about 1 inch long and has brown wings with black, wavy markings. The antennae are large and shaped like a feather. The female is larger, about 1 ½ inches long. Her wings are white with black markings. Her body is covered in brownish-yellow "fur" and her antennae are thin. She has wings, but can't fly! From late July to early August, the gypsy moth will mate and the female will lay eggs. The adults die after mating.
Gypsy Moth Pupa
This is the metamorphic stage. Within the pupal shell, the caterpillar's body is rearranging itself into an adult moth. The outer skin is reddish-brown and may be attached by several silk threads to a tree trunk, rock, or board, hiding itself from predators and parasites
General Information
The gypsy moth, Lymantria dispar, is one of North America's most devastating forest pests. The species originally evolved in Europe and Asia and has existed there for thousands of years. In either 1868 or 1869, the gypsy moth was accidentally introduced near Boston, MA by E. Leopold Trouvelot. About 10 years after this introduction, the first outbreaks began in Trouvelot's neighborhood and in 1890 the State and Federal Government began their attempts to eradicate the gypsy moth. These attempts ultimately failed and since that time, the range of gypsy moth has continued to spread. Every year, isolated populations are discovered beyond the contiguous range of the gypsy moth but these populations are eradicated or they disappear without intervention. It is inevitable that gypsy moth will continue to expand its range.
The gypsy moth is known to feed on on the foliage of hundreds of species of plants in North America but its most common hosts are oaks and aspen. Gypsy moth hosts are located through most of the coterminous US but the highest concentrations of host trees are in the southern Appalachian Mtns., the Ozark Mtns., and in the northern Lake States.
Gypsy moth populations are typically eruptive in North America; in any forest stand densities may fluctuate from near 1 egg mass per ha to over 1,000 per ha. When densities reach very high levels, trees may become completely defoliated. Several successive years of defoliation, along with contributions by other biotic and abiotic stress factors, may ultimately result in tree morality. In most northeastern forests, less than 20% of the trees in a forest will die but occasionally tree mortality may be very heavy.
Forest Effects
Despite over 100 years of presence in North America, researchers are still at a loss to explain and predict the extent of the changes in forest vegetation likely to take place through gypsy moth disturbance. A major concern is the potential loss of economically critical and ecologically dominant oak species. Most studies of forest compositional changes with gypsy moth defoliation indicate that less susceptible species will dominate the forest, so in effect, forests may have fewer gypsy moth problems in the future.
Natural Enemies
A variety of natural agents are known to kill gypsy moths in nature. These agents include over 20 insect parasitoids and predators that were introduced over the last 100 years from Asia and Europe. Small mammals are perhaps the most important gypsy moth predator, especially at low population densities. Birds are also known to prey on gypsy moths but at least in North America this does not substantially affect populations. A nucleopolyhedrosis virus usually causes the collapse of outbreak populations and recently an entomopathogenic fungus species has caused considerable mortality of populations in North America.
Videos
Pest of Deciduous Forest: Gypsy Moth
Gypsy Moth Decimate Forest - CBS News
Articles
Gypsy Moth Invasion
Hairy, Hungry and Here
Maps
Quarintene Zone
Defoliation
Life Cycle of a Gypsy Moth
Gypsy Moth Eggs
The female gypsy moth lays between 500 to 1,000 eggs in August. They are laid all at once in a mass that is covered with velvety, buff-colored hair from the female moth's body. The larva starts developing during the remaining warm days of summer. As winter approaches, the tiny larva goes into diapause. That means it shuts down and goes through the winter without growing or developing until spring. The eggs hatch in mid-May, just in time to start munching on new green leaves.
Gypsy Moth Larva
This stage is also known as caterpillar, the worm-like form of an insect. The larva is covered in long, stiff hairs. When it is very young, it's black. As the larva grows, pairs of colored warts appear running down the center of its back. The warts are red on the rear half and blue near the head.
Before the larvae settle down to feed, they will spread out through the forest by "ballooning." This means that the larva climbs to the top of the tree, spins a thread and dangles from it. When a breeze catches the larva, away it goes, usually landing within 150 yards of where it started. Although, on occasion, the larvae are blown long distances. This is one way the gypsy moth travels to new areas.
In order to grow, the larva must shed its skin. Gypsy moth caterpillars will shed their skin 4-5 times, about once a week. It is the larval stage of the moth that causes all the damage to trees as the caterpillars feed on leaves. By July, the larvae have reached maturity.
When the gypsy moth population explodes, the feeding larvae can strip trees of leaves. This is called defoliation. Defoliation is very stressful for trees and can leave them so weak that they can be killed by other pests which would not normally bother them. The hungry larvae feed on many types of trees, but they do have their favorites. These are the ones defoliated most frequently.
Gypsy Moth Adult
This is the adult stage of the insect. The male gypsy moth is about 1 inch long and has brown wings with black, wavy markings. The antennae are large and shaped like a feather. The female is larger, about 1 ½ inches long. Her wings are white with black markings. Her body is covered in brownish-yellow "fur" and her antennae are thin. She has wings, but can't fly! From late July to early August, the gypsy moth will mate and the female will lay eggs. The adults die after mating.
Gypsy Moth Pupa
This is the metamorphic stage. Within the pupal shell, the caterpillar's body is rearranging itself into an adult moth. The outer skin is reddish-brown and may be attached by several silk threads to a tree trunk, rock, or board, hiding itself from predators and parasites
Work Cited
"Gypsy moth (Portheria dispar)." DISCovering Science. Online ed. Detroit: Gale, 2003. Student Resource Center - Gold. Gale. Stroudsburg High School. 14 Nov. 2008 <http://find.galegroup.com/srcx/infomark.do? &contentSet=GSRC &type=retrieve &tabID=T001 &prodId=SRC-1 &docId=EJ2103201243 &source=gale &srcprod=SRCG &userGroupName=stro53037 &version=1.0.htm.>
McManus, M., and N. Schneeberger, eds. "Gypsy Moth." Aug. 1992. U.S. Department of Agriculture Forest Service. 13 Nov. 2008 <http://www.na.fs.fed.us/spfo/pubs/fidls/gypsymoth/gypsy.htm>.
University of Main Cooperative Extension, comp. "Gypsy Moth." 19 Aug. 2008. University of Maine Pest Management. 13 Nov. 2008 <http://pmo.umext.maine.edu/factsht/gypsy.htm>.